Centrifugal bowl



Oct. 4, 1955 N. E. BERGNER CENTRIFUGAL BOWL Filed Aug. 20,.1953

INVENTOR. fife/"e znar Beer W. Wm #mM United States Patent 2,719,668 7CENTRIFUGAL BOWL Nore Einar Bergner, Stockholm, Sweden, assignor toAktiebolaget Separator, Stockholm, Sweden, a corporation of SwedenApplication August 20, 1953, Serial No. 375,334 Claims priority,application Sweden September 4, 1952 12 Claims. (Cl. 233.32)

This invention relates to centrifugal separators and more particularlyto an improved centrifugal bowl for separating a feed into at least twoconstituents of different specific gravities.

The centrifugal bowl of the present invention has a separating chamberwhich preferably is of great length or axial extent as compared to itsdiameter. 'In any case, the bowl is characterized by having feedchannels'in'one end of the separating chamber for admitting the materialto be separated, these feed channels opening into the separating chamberat its periphery and serving to impart rotary movement to the feedmaterial, while in the other end of the separating chamber aresubstantially radial channels or flow spaces; and at least one dischargeopening is arranged in the central part of the separating chamber. 7

For a better understanding of the invention, reference may be had to theaccompanying drawing, in which the single illustration is a verticalsectional view, partly schematic, of apreferred form of the new bowl.

Referring to the drawing, the numeral 1 designates a centrifugal bowlmounted on a hollow drive shaft 1a which forms a feed channelfordelivering the material to be separated into .the separating chamber2. The flow of the 1 feed from channel 1b to chamber 2 is' by way of anumber of feed channels 3 arranged more or less perpendicularly to theshaft of the centrifugal bowl .and opening into the separating chamber 2at one endof .the bowl, the feed end. ,The channels 3 may bei'formed bymeans including radial vanes 3a underlyinga central baffle disc 3b. Atthe other end of the bowl, likewise in the separating chamber 2 aresubstantially radial channels 4. The centrifugal bowl is provided withtwo concentrically arranged discharge devices or channels 5 and 6, andthe discharge openings formed by these channels in the centrifugal bowlare located in-the central .part of the separating chamber.Theseparating chamber is provided at its periphery with an enlargementforming a sludge space or chamber 7 for:collection of separated sludge;and in the wall of the centrifugal bowl are sludge outlets 8, such asnozzles or the like, which preferably are directed backwards withrespect to the direction of rotation of the bowl. The separatedcomponents may be collected in the usual manner in receiving chambersformed by the stationary covers 9, 10 and 11.'

It will be observed that the separating chamber 2 has a central verticalaxis corresponding to the axis of rotation of the hollow drive shaft 1aof the bowl. This chamber also has opposed, axially spaced ends formedby disc 3b and the top of the bowl, respectively. The discharge openings5a and 6a, as shown, are located at a shorter distance from the chamberend 3b at which the inlet channels 3 are located than from the other endat which the channels 4 are located.

The material to be separated is preferably fed to the rotatingcentrifugal bowl 1 under pressure, and the feed channel 1b in the shaftshould therefore be directly connected to its stationary feed line bymeans of a sealing arrangement of conventional form (not shown). In thechannels 3 ,a rotational movement is imparted to the feed material whichthen flows in an axial direction throughthe separating chambersubstantially following its outer boundary surface. The heavierparticles in the material are thereby separated out and slide along thisouter boundary surface to the sludge chamber ,7, from which they arethen discharged through the nozzles 8. The light component, and theheavier particles which are more difiicult to separate, continue in anaxial direction to the other end of the bowl where. they are forcedthrough the channels .4 arranged therein (which may be formed, forexample, by means of radially directed vanes 4a) and inward toward thecentral. part of .the separating chamber, and then flow downward alongthe inner boundary. surface of the separating chamber in an axialdirection toward the openings of the discharge channels Sand 6. Thismaterial is finally discharged from the separating chamber through thedischarge channels 5 and 6, which may be formed by concentric tubes.

It is to be noted that the material being separated does not to anyappreciable extent pass through-the separating chamber 2 directly fromthe mouths of the feed channels 3 to the mouths .of the dischargechannels 5 and 6, but mainly follows the arrows indicated on thedrawing. If the material should take the shortest way through theseparating chamber, it would slide because there are no vanes, blades orthe like in this part of the separating chamber. Such a sliding movementcauses an extraordinarily high counter-pressure which increases rapidlyaccording to the throughput rate. Owing to the conveying effect .of thechannels 3 arranged in the feed end of ;the separating chamber, thematerial does .not take the shortest waythrough .this chamber butinstead passes axially, in the manner described :above, first in onedirection along the outer boundary surface of the separating chamber.and then ;in the .opposite direction along the inner boundary surfaceof .the separating chamber. Thematerial is thus subjected to anextremely effective separation, partly .due to its long path through theseparating chamber .and partly because this path in general is situatedin the .outer part of the separating chamber, which from the .point .of.view of separation is the most eflicient part. Due to this flow path,the diameter of the separating chamber may be very small, whereby thecentrifugal bowl may .be operated at a relatively high speed :of:rotation, which is -of importance because the smaller the diameter, thegreater the acceleration will be for given stresses in the centrifugalbowl. The channels 4 in the upper part of the separating chamber allowthe material to move inward at :a low counter-pressure, since they actto prevent sliding of the material relative to the bowl.

If the sludge particles vary considerably in size, the smallestparticles (i. e., those which are most difiicult to separate) will bedischarged through the outlet 5 together with the liquid component. Bysliding from channel 5 to channel 6, however, a lighter liquid can alsobe separated off, the purified liquid thus discharging through channel 6and the lighter sludge through channel 5. Since the sliding, aspreviously mentioned, causes a considerable counter-pressure, the amountwhich discharges through the inner channel 6 will be smaller than thatdischarging through the outer channel 5.

From the above description of the operation of the centrifugal bowl, itis clear that the discharge openings 5a and 6a for the lightercomponents located in the central part of the centrifugal bowl may beplaced quite near the feed end of the centrifugal bowl, and yet there isno risk of the feed material taking the shortest path from the feedchannels 3, which open at the periphery of the separating chamber, tothe discharge openings 5a and 6a. Thus, a very advantageous elongationof the flow path of the material through the separating chamber isobtained.

' The centrifugal bowl here illustrated is to be regarded only as anexample of the present invention and can therefore be modified. In caseof small sludge quantities to be separated, the sludge outlets 8 (andpossibly also the enlargement 7 serving as a sludge chamber) may beeliminated. Also, the sludge outlets 8 and the sludge chamber '7 may belocated at a greater or smaller distance from the feed end of thecentrifugal bowl than that shown on the drawing.

The substantially radial channels 4 at the other end of the centrifugalbowl may consist of the spaces between radially directed vanes, bladesor the like, which are shown at 4a It is also to be noted that the shaft1a of the centrifugal bowl of the present invention need not be driven,since rotary motion in the separating chamber can be imparted to thematerial in the same manner as in a cyclone. Thus, the necessaryrotation of the feed material may be effected, without rotating the bowl1, by simply arranging the feed channels 3 so that they open intochamber 2 substantially tangentially, as is Well-known and conventionalin cyclones.

It is further pointed out that the separator may also be used forseparation of two liquid components from one another, in that thelighter liquid component is discharged through outlet 6, and the otherliquid component through outlet 5, whereas the sludge, as mentionedabove, either is discharged through the nozzle openings 8 or iscollected in the sludge chamber 7. On the otherhand, more than twoliquid components may be taken out through a corresponding number ofconcentric discharge openings in the central portion of the separatingchamber. The nozzle openings at the periphery also may be used asoutlets for the heaviest liquid component instead of being used assludge outlets, provided that the material being separated contains noheavy sludge.

I claim:

1. In a centrifugal bowl forming a separating chamber having a centralaxis and opposed, axially-spaced ends, the combination of means formingan inlet channel for the feed material at one end of the chamber, saidchannel opening into the separating chamber at its periphery and beingoperable to impart a rotary movement to the feed material, means formingsubstantially radial channels in said chamber at the other end thereofand in which material from said inlet channel, after traversing thechamber 3. A centrifugal bowl according to claim 1, in which said meansforming the inlet channel include generally radial vanes forming aplurality of inlet channels, the bowl also having externally thereof acentral hollow shaft forming a feed channel leading directly to saidinlet channels.

4. A centrifugal bowl according to claim 1, comprising also a centralshaft mounting the bowl for rotation on said axis.

5. A centrifugal bowl according to claim 1, in which said dischargeopening is located at a shorter distance from said first end of thechamber than from the other end thereof.

6. A centrifugal bowl according to claim '1, in which the separatingchamber intermediate its ends is provided with an enlargement at itsperiphery forming a sludge space for collecting sludge separated fromthe feed material.

7. A centrifugal bowl according to claim 1, in which the separatingchamber intermediate its ends is provided with an enlargement at itsperiphery forming a sludge space for collecting sludge separated fromthe feed material, said sludge space being located near said other endof the separating chamber.

8. A centrifugal bowl according to claim 1, in which the separatingchamber is provided with sludge outlets in the peripheral wall of thebowl.

9. A centrifugal bowl according to claim 1, in which the separatingchamber is provided with sludge outlets in the peripheral wall of thebowl, said sludge outlets being located near said other end of theseparating chamber.

10. A centrifugal bowl according to claim 1, in which a the separatingchamber intermediate its ends is provided with an enlargement at itsperiphery forming a sludge space for collecting sludge separated fromthe feed material, said sludge space being located near said other endof the separating chamber, there being sludge outlets in the peripheralpart of said sludge space.

11. A centrifugal bowl according to claim 1, comprising also a seconddischarge device in the bowl forming a second discharge opening in thecentral part of said chamber but at a dilferent radius than the firstdis charge opening.

' 12. A centrifugal bowl according to claim 1, in which said dischargedevice is a central tube in the bowl,,the bowl also having a seconddischarge tube concentric with the first and forming a second dischargeopening.

References Cited in the file of this patent UNITED STATES PATENTS1,870,113 Hawkins et a1. Aug. 2, 1932 2,422,882 Bramley June 24, 1947FOREIGN PATENTS 111,848 Germany July 16, 1900

